In general, a multimedia system for a vehicle is a system for providing services, such as a car audio service, a moving image service, an analog broadcasting service, a digital broadcasting service, a telematics service, a communication service, and other services, within the vehicle. Such a multimedia system for a vehicle may be implemented in various forms, such as a car audio system.
FIG. 1 is a diagram schematically illustrating the location where an antenna module and a tuner unit module are conventionally installed in a vehicle, and FIG. 2 is a diagram schematically illustrating a conventional configuration in which the antenna module and the tuner unit module are coupled through coaxial cables (refer to Korean Patent Application Publication No. 2011-0127541).
Referring to FIGS. 1 and 2, the conventional multimedia system for a vehicle has a structure in which an antenna module 20 for sending and receiving radio signals (broadcasting and communication signals, etc.) is installed on the external surface of the vehicle 10 on the back side of a roof panel 12 and a tuner unit module 30 for processing a signal received by the antenna module 20 is embedded in a car audio installed on the instrument panel side of the vehicle and coupled through a plurality of coaxial cables 40. Furthermore, a low noise amplifier (LNA) for improving the reception sensitivity of an antenna is built in the antenna module 20, and a power line for supplying corresponding separate power is installed in the antenna module 20.
However, the conventional multimedia system for a vehicle having the aforementioned configuration is problematic in that a radio signal is deteriorated because the tuner unit module 30 is configured to be connected to the antenna module 20 mounted on the external surface of the roof panel 12 of the vehicle through the plurality of coaxial cables 40 at a remote distance. That is, a cable loss and a matching loss are generated because the coaxial cable 40 having a length of about 5 meters is used in order for a radio signal received through the antenna module 20 to be transferred to the tuner unit module 30 built in a car audio device. Furthermore, there is a problem in that the reception sensitivity of a broadcasting signal is significantly reduced because the tuner unit module 30 mounted on the car audio device is influenced by the wiring harness noise of a frequency band similar to a broadcasting frequency generated from a vehicle engine or driving motor because the engine room of the vehicle and the car audio device are closely disposed. Furthermore, the conventional multimedia system for a vehicle is problematic in that an installation cost is high when constructing a multimedia system because a plurality of the expensive and long coaxial cables 40 and connectors (not illustrated) are used to couple the antenna module 20 and the tuner unit module 30, that workability according to a system construction is deteriorated because a complicated cable task for coupling modules is required, and that the fuel mileage of the vehicle is reduced because the weight of the vehicle is increased due to the installation of the plurality of coaxial cables.